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Abstract:

Polymeric composite materials, particularly highly filled polyurethane
composite materials are described herein. Such highly filled polyurethane
composite materials may be formed by reaction and extrusion of one or
more polyols, one or more di- or poly-isocyanates, and from about 45 to
about 85 weight percent of inorganic filler such as fly ash. Certain
polyols, including plant-based polyols can be used. Certain composite
materials also contain chain extenders and/or crosslinkers. The
polyurethane composite material may also contain fibers such as chopped
or axial fibers which further provide good mechanical properties to the
composite material. Shaped articles containing the polyurethane composite
material have been found to have good mechanical properties, such that
the shaped articles are suitable for building applications.

Claims:

1. A polyurethane composite material comprising: a polyurethane formed by
reaction of a reaction mixture comprising: one or more monomeric or
oligomeric poly- or di-isocyanates; a first polyol, which is a rigid
polyol, having a first hydroxyl number in the range of about 320 mg KOH/g
to about 600 mg KOH/g; and a second polyol having a second hydroxyl
number, wherein the second hydroxyl number is at least about 20 mg KOH/g
and is less than the first hydroxyl number; wherein at least one of the
first polyol and the second polyol are plant based polyester polyols; a
blowing agent; wherein the blowing agent is water, which is present at a
concentration of less than about 0.4% based upon the weight of the
composite material; wherein the ratio of the first polyol to the second
polyol is about 3 to about 20; about 60 to about 85 weight percent of an
inorganic filler, based upon the weight of the composite material,
wherein the inorganic filler comprises coal ash; wherein the reaction
mixture is substantially free of halogenated hydrocarbons; an ultraviolet
light stabilizer; about 0.1 to about 10 weight percent of a reinforcing
fiber based upon the weight of the composite material; wherein the
reinforcing fiber has a length in the range of 0.125 inches to about 1
inch; wherein the composite material has a density of about 65
lbs/ft3 to about 85 lbs/ft.sup.3.

2. The polyurethane composite material of claim 1, wherein the material
comprises about 65 to about 75 weight percent of the inorganic filler.

3. The polyurethane composite material of claim 1, wherein the material
comprises about 65 to about 85 weight percent of the inorganic filler.

8. The polyurethane composite material of claim 1, wherein the reaction
mixture further comprises at least one of ethylene glycol, 1,4-butane
diol, trimethylolpropane, glycerol, and sorbitol. The polyurethane
composite material of claim 1, wherein the one or more selected from a
chain extender and a cross linker is selected from the group consisting
of ethylene glycol, 1,4-butane diol, trimethylolpropane, glycerol, and
sorbitol.

9. The polyurethane composite material of claim 1, wherein the material
comprises a chain extender, the chain extender being an organic compound
having two or more hydroxyl groups.

10. The polyurethane composite material of claim 1, wherein a chain
extender is reacted with the one or more monomeric or oligomeric poly- or
di-isocyanates.

11. A polyurethane composite material comprising: a polyurethane formed
by reaction of a reaction mixture of: one or more monomeric or oligomeric
poly- or di-isocyanates; and a first polyol, which is a rigid polyol,
having a first hydroxyl number in the range of about 320 mg KOH/g to
about 600 mg KOH/g; and a second polyol having a second hydroxyl number,
wherein the second hydroxyl number is at least about 20 mg KOH/g and is
substantially less than the first hydroxyl number; wherein at least one
of the first polyol and the second polyol are plant based polyester
polyols; water in an amount that provides a composite material having a
density of about 30 lbs/ft3 to about 85 lbs/ft3; wherein the
ratio of the first polyol to the second polyol is about 3 to about 20;
about 40 to about 85 weight percent inorganic filler, wherein the
inorganic filler comprises coal ash; and reinforcing fiber having a
length in the range of 0.125 inches to about 1 inch.

16. The polyurethane composite material of claim 11, wherein the material
comprises about 0.01 wt % to about 0.5 wt % of the at least one coupling
agent.

17. A method of forming a polyurethane composite material, the method
comprising: providing a first polyol, which is a rigid polyol, having a
first hydroxyl number in the range of about 320 mg KOH/g to about 600 mg
KOH/g; providing a second polyol, which is a flexible polyol, having a
second hydroxyl number, wherein the second hydroxyl number is at least
about 20 mg KOH/g and is substantially less than the first hydroxyl
number; wherein the ratio of rigid polyol to flexible polyol is about 3
to about 20; wherein one of the first polyol and the second polyol are
plant based polyester polyols; providing at least one poly or
di-isocyanate; providing about 45 to about 85 weight percent of an
inorganic filler based upon the weight of the composite material;
providing a blowing agent consisting essentially of water at a
concentration of less than about 0.4% based upon the weight of the
composite material; extruding the first polyol, the second polyol, the at
least one poly or di-isocyanate, and the inorganic filler into an
extruded mixture; and containing the extruded mixture in a forming
device; wherein the resulting polyurethane composite material has a
density in the range of about 30 lbs/ft3 to about 85 lbs/ft.sup.3.

18. The method of claim 17, further comprising placing the extruded
mixture in a mold and shaping the extruded mixture in the mold; wherein
the mold is formed by one or more belts of a forming device.

19. The method of claim 17, further comprising mixing the at least one
polyol with a solvent.

20. The method of claim 19, wherein the solvent comprises about to 2 to
about 10 wt % of one or more solvents selected from the group consisting
of pentane, hexane, and ethyl acetate.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a continuation of U.S. patent
application Ser. No. 11/691,449, filed Mar. 26, 2007, which claims the
priority benefit under 35 U.S.C. §119(e) of the provisional
applications 60/785,726, filed Mar. 24, 2006 and 60/785,749, filed Mar.
24, 2006. The present application incorporates in their entireties all of
these documents herein.

BACKGROUND OF THE INVENTION

[0002] 1. Field

[0003] The invention relates to highly filled polyurethane composite
materials, methods of forming the same, and articles including the same.
It particularly relates to the material used in the formation of highly
filled polyurethane composite materials.

[0004] 2. Description of the Related Technology

[0005] Polymeric composite materials that contain organic or inorganic
filler materials have become desirable for a variety of uses because of
their excellent mechanical properties, weathering stability, and
environmental friendliness.

[0006] These materials can be are relatively low density, due to their
foaming, or high density when unfoamed, but are extremely strong, due to
the reinforcing particles or fibers used throughout. Their polymer
content also gives them good toughness (i.e., resistance to brittle
fracture), and good resistance to degradation from weathering when they
are exposed to the environment. This combination of properties renders
some polymeric composite materials very desirable for use in building
materials, such as roofing materials, decorative or architectural
products, outdoor products, insulation panels, and the like.

SUMMARY OF THE INVENTION

[0007] Described herein are polymeric composite materials. In some
embodiments, the polymeric composite materials contain some amount of
filler content. In particular embodiments, a polyurethane composite
material may include a polyurethane formed by reaction of a reaction
mixture of one or more monomeric or oligomeric poly- or di-isocyanates;
and at least one polyol. In preferred embodiments the one or more
monomeric or oligomeric poly- or di-isocyanates may include an MDI. In
preferred embodiments, the at least one polyol may be selected from a
plant-based polyol or an oil based polyol. Suitable polyols include
polyester polyols, polyether polyols, polycarbonate polyols, polyacrylic
polyols, and others described herein. More than one polyol may be used in
accordance with certain embodiments.

[0008] In some embodiments, the composite material may additionally
include an inorganic filler. In some embodiments, the inorganic filler
may include coal ash such as fly ash or bottom ash or mixtures of fly and
bottom ash. In some embodiments, the polyurethane composite material
comprises about 40-85% inorganic filler. In some embodiments, the
polyurethane composite material comprises about 65-75% inorganic filler.
In some embodiments, the polyurethane composite material comprises about
60-85% inorganic filler.

[0009] In particular embodiments, the polyurethane composite material may
additionally include one or more selected from the group consisting of
chain extenders, cross linkers, and combinations thereof. In some
embodiments, the polyurethane composite material includes a chain
extender. In some embodiments, the chain extender is one or more selected
from the group consisting of ethylene glycol, glycerin, 1,4-butane diol,
trimethylolpropane, glycerol, sorbitol, and combinations thereof. In some
embodiments, the chain extender is an amine chain extender, for example
diamines. In certain embodiments, the polyurethane composite material
includes glycol extenders. In some embodiments, the chain extender is
organic compound having two or more hydroxyl groups.

[0010] In some embodiments, the polyurethane composite material is in the
form of a shaped article. In certain embodiments, the shaped article is
selected from the group consisting of roofing material, siding material,
carpet backing, synthetic lumber, building panels, scaffolding, cast
molded products, decking material, fencing material, marine lumber,
doors, door parts, moldings sills, stone, masonry, brick products, post
signs, guard rails, retaining walls, park benches, tables slats, and
railroad ties. In certain embodiments, a solid surface article includes a
portion, wherein the portion includes at least some of the polyurethane
composite material as described herein.

[0011] In some embodiments, the polyurethane composite material includes
fibrous materials. In certain embodiments, the fibrous material may be
chopped fibers such as chopped fiber glass or chopped basalt fiber. In
certain embodiments, the polyurethane composite material includes axially
oriented fiber rovings disposed on, in, or beneath the surface of the
composite.

[0012] The aforementioned components may be reacted in accordance with
certain techniques and other additives. For example, the polyurethane
composite material may be mixed and reacted in an extruder. In certain
embodiments, a method of forming a polyurethane composite material
includes providing at least one polyol, providing at least one poly or
di-isocyanate, providing an inorganic filler; and extruding the at least
one polyol, the at least one poly or di-isocyanate, and the inorganic
filler, into an extruded mixture. In accordance with certain embodiments,
additives such as chain extenders and coupling agents may be extruded. In
certain embodiments, the method further includes placing the extruded
mixture in a mold. In some embodiments, the extruded mixture may be
shaped in the mold. In certain embodiments, the mold is formed by one or
more belts of a forming device.

[0013] In certain embodiments, there may be certain advantages by mixing
the at least one polyol with a solvent. For example, it has been
discovered that treatment or mixing with a solvent may result in thicker
and harder skin of the formed composite material. In some embodiments,
the solvent is an organic solvent. In other embodiments, the solvent is
selected from the group consisting of pentane, hexane, carbon
tetrachloride, trichloroethylene, methylene chloride, chloroform, methyl
chloroform, perchloroethylene, and ethyl acetate. In particular
embodiments, about 2 to about 10 weight percent of the solvent may be
added to one or more components prior to mixing and/or extruding.

[0014] In some embodiments, a method of forming a polyurethane composite
material includes providing at least one polyol, providing at least one
poly or di-isocyanate, providing about 45 to about 85 weight percent of
an inorganic filler, providing excess blowing agent; extruding the at
least one polyol, the at least one poly or di-isocyanate, the inorganic
filler, and the excess blowing agent into an extruded, foaming mixture,
and containing the extruded mixture in a mold. In certain embodiments,
the mold sufficiently restrains the foaming mixture to provide a desired
shape or density to the composite material. In some embodiment,
restraining such foaming composite material may result in higher strength
and stiffness of the composite material. This may result from the
alteration of cell size and cell structure.

[0015] In some embodiments, a method of coating a solid surface article
includes depositing the polyurethane composite material as described
herein on a solid surface article, shaping the polyurethane composite
material on the solid surface article in a mold; and curing the
polyurethane composite material on the solid surface article.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] Described herein are polymeric composite materials. In particular
embodiments, the polymeric composite material include polyurethane
composite materials. While the embodiments described herein are
specifically related to polyurethane composite materials, the technology
may also be applicable to many other polymeric resins, particularly those
related to highly filled thermosetting polymers. Generally, a
polyurethane is any polymer consisting of a chain of organic units joined
by urethane linkages. Typically, a polyurethane may be formed by reaction
of one or more monomeric or oligomeric poly- or di-isocyanates (sometimes
referred to as "isocyanate") and at least one polyol, such as a polyester
polyol or a polyether polyol. These reactions may further be controlled
by various additives and reaction conditions. For example, one or more
surfactants may be used to control cell structure and one or more
catalysts may be used to control reaction rates. Advantageously, the
addition of certain polyol and isocyanate monomers and certain additives
(e.g., catalysts, crosslinkers, surfactants, blowing agents), may produce
a polyurethane material that is suitable for commercial applications.

[0017] As is well known to persons having ordinary skill in the art,
polyurethane materials may also contain other polymeric components by
virtue of side reactions of the polyol or isocyanate monomers. For
example, a polyisocyanurate may be formed by the reaction of optionally
added water and isocyanate. In addition, polyurea polymers may also be
formed. In some embodiments, such additional polymer resins may have an
effect on the overall characteristics of the polyurethane composite
material.

[0018] It has further been found that some portion of the polymeric
component of polyurethanes may be replaced with one or more fillers such
as particulate material and fibrous materials. With the addition of such
fillers, the polyurethane composite materials may still retain good
chemical and mechanical properties. These properties of the polyurethane
composite material allows for its use in building materials and other
structural applications. Advantageously, the polyurethane composite
material may contain large loadings of filler content without
substantially sacrificing the intrinsic structural, physical, and
mechanical properties of the polymer. Such building materials would have
advantages over composite materials made of less or no filler. For
example, the building materials may be produced at substantially
decreased cost. Furthermore, decreased complexity of the process
chemistry may also lead to decreased capital investment in process
equipment.

[0019] In one embodiment, the composite materials have a matrix of polymer
networks and dispersed phases of particulate or fibrous materials. The
polymer matrix includes a polyurethane network formed by the reaction of
a poly- or di-isocyanate and one or more polyols. The matrix is filled
with a particulate phase, which can be selected from one or more of a
variety of components, such as fly ash particles, axially oriented
fibers, fabrics, chopped random fibers, mineral fibers, ground waste
glass, granite dust, slate dust or other solid waste materials.

[0020] Such polyurethane composite materials may be formed with a desired
density, even when foamed, to provide structural stability and strength.
In addition, the polyurethane composite materials can be easily tuned to
modify its properties by, e.g., adding oriented fibers to increase
flexural stiffness, or by adding pigment or dyes to hide the effects of
scratches. Also, such polyurethane composite materials may also be
self-skinning, forming a tough, slightly porous layer that covers and
protects the more porous material beneath. Such tough, continuous, highly
adherent skin provides excellent water and scratch resistance. In
addition, as the skin is forming, an ornamental pattern (e.g., a
simulated wood grain) can be impressed on it, increasing the commercial
acceptability of products made from the composite. In one embodiment, an
ornamental pattern may be in a mold, and the pattern is molded into the
composite material,

[0021] Described herein are certain improvements that may be used in the
production of polyurethane composite materials. Some previously described
polyurethane composite material systems are included in U.S. patent
application Ser. No. 10/764,012, filed Jan. 23, 2004, and entitled
"FILLED POLYMER COMPOSITE AND SYNTHETIC BUILDING MATERIAL COMPOSITIONS,"
now published as U.S. Patent Application Publication No. 2005-163969-A1,
and U.S. patent application Ser. No. 11/190,760, filed Jul. 27, 2005, and
entitled "COMPOSITE MATERIAL INCLUDING RIGID FOAM WITH INORGANIC
FILLERS," now published as U.S. Patent Application Publication No.
2007-0027227 A1, which are both hereby incorporated by reference in their
entireties. However, in no way, are such polyurethane composite material
systems intended to limit the scope of the improvements described in the
present application.

[0022] The various components and processes of preferred polyurethane
composite materials are further described herein:

Monomeric or Oligomeric Poly or Di-isocyanates

[0023] As discussed above, one of the monomeric components used to form a
polyurethane polymer of the polyurethane composite material is one or
more monomeric or oligomeric poly or di-isocyanates. The polyurethane is
formed by reacting a poly- or di-isocyanate. In some embodiments, an
aromatic diisocyanate or polyisocyanate may be used.

[0024] In certain embodiments methylene diphenyl diisocyanate (MDI) is
used. The MDI can be MDI monomer, MDI oligomer, or mixtures thereof. The
particular MDI used can be selected based on the desired overall
properties, such as the amount of foaming, strength of bonding to the
inorganic particulates, wetting of the inorganic particulates in the
reaction mixture, strength of the resulting composite material, and
stiffness (elastic modulus). Although toluene diisocyanate can be used,
MDI is generally preferable due to its lower volatility and lower
toxicity. Other factors that influence the particular MDI or MDI mixture
are viscosity (a low viscosity is desirable from an ease of handling
standpoint), cost, volatility, reactivity, and content of 2,4 isomer.
Color may be a significant factor for some applications, but does not
generally affect selection of an MDI for preparing an article.

[0025] Light stability is also not a particular concern for selecting MDI
for use in the composite material. According to some embodiments, the
composite material allows the use of isocyanate mixtures not generally
regarded as suitable for outdoor use, because of their limited light
stability. When used in to form the polyurethane composite material, such
materials surprisingly exhibit excellent light stability, with little or
no yellowing or chalking. Suitable MDI compositions include those having
viscosities ranging from about 25 to about 200 cp at 25° C. and
NCO contents ranging from about 30% to about 35%. Generally, isocyanates
are used that provide at least 1 equivalent NCO group to 1 equivalent OH
group from the polyols, desirably with about 5% to about 10% excess NCO
groups. Useful polyisocyanates also may include aromatic polyisocyanates.
Suitable examples of aromatic polyisocyanates include 4,4-diphenylmethane
diisocyanate (methylene diphenyl diisocyanate), 2,4- or 2,6-toluene
diisocyanate, including mixtures thereof, p-phenylene diisocyanate,
tetramethylene and hexamethylene diisocyanates, 4,4-dicyclohexylmethane
diisocyanate, isophorone diisocyanate, mixtures of 4,4-phenylmethane
diisocyanate and polymethylene polyphenylisocyanate. In addition,
triisocyanates such as, 4,4,4-triphenylmethane triisocyanate
1,2,4-benzene triisocyanate; polymethylene polyphenyl polyisocyanate; and
methylene polyphenyl polyisocyanate, may be used. Isocyanates are
commercially available from Bayer USA, Inc. under the trademarks MONDUR
and DESMODUR. Suitable isocyanates include Bayer MRS-4, Bayer MR Light,
Dow PAPI 27, Bayer MR5, Bayer MRS-2, and Huntsman Rubinate 9415.

[0026] In certain embodiments, the average functionality of the isocyanate
component is between about 1.5 to about 4. In other embodiments, the
average functionality of the isocyanate component is about 3. In other
embodiments, the average functionality of the isocyanate component is
less than about 3, including, about 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4,
2.5, 2.6, 2.7, 2.8, and 2.9. In some embodiments, the isocyanate has a
functionality of about 2. Some of these embodiments produce polyurethane
composite materials with higher mechanical strengths and lower costs than
polyurethane composite material comprising more than about 2.

[0027] As indicated above, the isocyanate used in the invention is reacted
with one or more polyols. In general, the ratio of isocyanate to polyol
(isocyanate index), based on equivalent weights (OH groups for polyols
and NCO groups for isocyanates) is generally in the range of about 0.5:1
to about 1.5:1, more particularly from about 0.8:1 to about 1.1:1, and in
another embodiment, from about 0.8:1 to about 1.2:1. Ratios in these
ranges provide good foaming and bonding to inorganic particulates, and
yields low water pickup, fiber bonding, heat distortion resistance, and
creep resistance properties. However, precise selection of the desired
ratio will be affected by the amount of water in the system, including
water added per se as a foaming agent, and water introduced with other
components as an "impurity."

[0028] In some embodiments, an isocyanate may be selected to provide a
reduced isocyanate index. It has been discovered that the isocyanate
index can be reduced without compromising the polyurethane composite
material's chemical or mechanical properties. It is additionally
advantageous according to some embodiments to use an isocyanate with a
reduced isocyanate index as isocyanates are generally higher priced than
polyols. Thus, a polyurethane system formed by an isocyanate monomer with
a reduced isocyanate index may result in reduced cost of producing the
total system.

Polyols

[0029] According to some embodiments, the polyurethane polymer is a
reaction product of one or more polyols with an isocyanate. The one or
more polyols used may be single monomers, oligomers, or blends. Mixtures
of polyols can be used to influence or control the properties of the
resulting polymer network and composite material. The properties,
amounts, and number of polyols used may be varied to produce a desired
polyurethane composite material.

[0030] It is generally desirable to use polyols in liquid form, and
generally in the lowest viscosity liquid form available, as these can be
more easily mixed with the inorganic particulate material. So-called "EO"
tipped polyols can be used; however their use is generally avoided where
it is desired to avoid "frosting" of the polymer material when exposed to
water.

[0032] In some embodiments, plant-based polyols are used as at least one
polyol. These polyols are lower in cost, and not dependent on the price
and availability of petroleum. In some embodiments, the plant-based
polyols provide a polyurethane system that is substantially identical to
that provided by oil-based polyols. In other embodiments, plant-based
polyols can be used to replace at least a portion of the oil-based
polyols. By employing plant-based polyols, the polyurethane composite
material is more environmentally safe and friendly. In addition, certain
equipment used to handle and dispose of oil-based polyols may be costly.

[0033] In some embodiments, the at least one polyol is a polyester polyol
that is substantially resistant to water soaking and swelling. Thus,
these polyols can be used in the formation of polyurethane composite
materials which, when cured, attracts less water. In certain cases, the
polyester polyols absorb less water than polyether polyols. However, in
some embodiments, polyester polyols and polyether polyols can be mixed in
the formation of polyurethane composite material to provide better water
resistance.

[0034] Some embodiments of the polyurethane composite material comprise at
least one polycarbonate polyol. These embodiments provide higher impact
and/or chemical resistance, as compared to polyurethane composite
material made from polyester and/or polyether polyols. However,
combinations of polycarbonate polyols, polyester polyols, and polyether
polyols can be used in systems with high inorganic fillers to provide the
desired mechanical and physical property of the polyurethane composite
material. In some embodiments, building products comprising the
polyurethane composite materials which employ at least one polyester
polyol demonstrate improved water resistance.

[0035] In some embodiments, at least some phenolic polyols are used to
make polyurethane composite materials which have improved flame
retardancy as compared to those polyurethane composite materials that are
not made from phenolic polyols. Such polyurethane composite materials may
also be fire and smoke resistance.

[0036] In other embodiments, the polyurethane composite materials are made
from at least one acrylic polyol. In some embodiments, the polyurethane
composite materials made from the at least one acrylic polyol demonstrate
improved weathering as compared to those that are not made from at least
one acrylic polyol. In other embodiments, the polyurethane composite
materials are made from at least one acrylic polyol exhibit substantially
no discoloration when exposed to sunlight.

[0037] In one embodiment, a first polyol having a first hydroxyl number
and a second polyol having a second hydroxyl number less than the first
hydroxyl number may be used. Such combination of polyols form a first
polyurethane that is less rigid than a second polyurethane that would be
formed by the reaction of the first polyol in the absence of the second
polyol. In some embodiments, the first polyol has a hydroxyl number
ranging from about 250 to about 500 mg KOH/g. In some embodiments, the
first polyol has a hydroxyl number ranging from about 300 to about 450 mg
KOH/g. In some embodiments, the first polyol has a hydroxyl number
ranging from about 320 to about 400 mg KOH/g. In some embodiments, the
first polyol has a hydroxyl number ranging from about 350 to about 500 mg
KOH/g. In some embodiments, the first polyol has a hydroxyl number
ranging from about 370 to about 600 mg KOH/g. In some embodiments, the
second polyol has a hydroxyl number less than the first polyol. In some
embodiments, the second polyol has a hydroxyl number ranging from about
20 to about 120 mg KOH/g. In some embodiments, the second polyol has a
hydroxyl number ranging from about 20 to about 70 mg KOH/g. In some
embodiments, the second polyol has a hydroxyl number ranging from about
30 to about 60 mg KOH/g. In some embodiments, the second polyol has a
hydroxyl number ranging from about 50 to about 75 mg KOH/g. In some
embodiments, the second polyol has a hydroxyl number ranging from about
40 to about 60 mg KOH/g. In some embodiments, the second polyol has a
hydroxyl number ranging from about 30 to about 50 mg KOH/g.

[0038] For example, a first polyol such as Bayer's MULTRANOL 4500 may be
used in combination with Bayer's ARCOL LG-56 and MULTRANOL 3900. In this
case, the first polyol has a hydroxyl number ranging from 365-395 mg
KOH/g. For ARCOL LG-56, the second polyol has a hydroxyl number ranging
from 56.2 to 59.0 mg KOH/g. For MULTRANOL 3900 has a hydroxyl number
ranging from 33.8 to 37.2 mg KOH/g. However, these examples are not
intended to be limiting. Any number of polyol as described above may be
selected for the hydroxyl number in controlling the flexibility or
rigidity of a polyurethane product.

[0039] In one embodiment, mixture of polyols can be used to achieve the
desired mechanical strength and rigidity of the final polyurethane
composite material. In some embodiments, polyols with OH functionality
between about 2 to about 7 can be used. In other embodiments, the average
functionality of the polyols is between about 4 to about 7. The
polyurethane composite materials become less expensive because the amount
of isocyanate needed to react with the polyols to substantially form the
desired polyurethane decreases. While this in some case may increase the
rubberiness, non-brittleness, or flexibility of the polyurethane
composite material, the correct balance of these functional polyols with
OH functionality, between about 4 to about 8, maintains the mechanical
properties of the polyurethane composite material, as compared to a
polyurethane composite material made from polyols with an average
functionality less than 4.

[0040] In some embodiments, the polyurethane composite material is made by
using higher functional polyols in place of polyols having an average
functionality of 2 or 3. In these embodiments, the polyurethane composite
material has more cross linking. Some embodiments have higher impact
strength, flexural strength, flexural modulus, chemical resistance, and
water resistance as compared to the polyurethane composite material
formed by polyols having a functionality of about 2 to about 3.

[0041] In some embodiments, the polyurethane composite material is made by
using more than one polyol with different OH numbers to give the same
weighted average OH number. Such polyurethane composite materials yield a
more segmented polymer. By allowing many polyols of different
functionality and/or molecular weight to be mixed together to make the
needed OH number to balance the number of isocyanate groups, the
orderliness of the resulting polymer chain is more segmented and less
likely to align together. In some embodiments, the polyurethane composite
material comprises three, four, five, or six types of polyols of
different functionality and/or molecular weight. For example, a
polyurethane system can be made from combination of multiple types of
polyols, wherein at least one first polyol has an average functionality
of about 2, wherein at least one second polyol has an average
functionality of about 4, and wherein at least one third polyol has an
average functionality of about 6. In one embodiment, the overall number
of hydroxyl groups may be adjusted with varying polyols. In some
embodiments, combinations of polyols with great number of hydroxyl groups
may be blended with smaller quantities of polyols with less hydroxyl
groups in order to produce a desired overall number of hydroxyl groups,
which will react with the isocyanate.

[0042] In some embodiments, impact strength of the polyurethane composite
material is greater than polyurethane composite materials comprising
polyols of the same or substantially similar functionality and/or
molecular weight. Although the two polyurethane compositions may comprise
polyols with substantially similar average functionality and/or molecular
weight, the polyurethane composition comprising polyols with
substantially different functionality may exhibit improved mechanical
properties such as impact strength. In some embodiments, polyurethane
composite materials comprising polyols of multiple functionalities are
more resistant to stress cracking.

[0043] Other embodiments of the polyurethane composite material are made
from at least one polyol with a molecular weight from about 2000 to about
8000. These polyurethane composite materials exhibit an integral skin. In
some embodiments, the skin is thicker. In other embodiments, the skin is
less porous and harder. In some embodiments, the use of at least one
polyol with a molecular weight from about 2000 to about 8000 results in
the migration of the at least one polyol to migrate to the outer surface
of the polyurethane composite material, thus allowing more outer skin to
be formed.

[0044] In one embodiment, mixtures of two or more polyols may be used. In
some embodiments, each polyol of a multi-polyol polyurethane system may
be chosen for the various mechanical and chemical properties that result
in the polyurethane composite produced as a result of using the polyol.
For example, it is known to persons having ordinary skill in the art that
polyols are often classified as rigid or flexible polyols based on
various properties of the individual polyol and the overall flexibility
of a polyurethane polymer produced from the respective polyols.
Typically, the rigidity or flexibility of the polyurethane formed from
any single polyol may be governed by one or more of the hydroxyl number,
functionality, and molecular weight of the polyol. As such, one or more
polyols with different characteristics may be used to control the
physical and mechanical characteristics of the polyurethane composite
material.

[0045] In one embodiment, the amount of rigid polyol is carefully
controlled in order to avoid making the composite too brittle. In some
embodiments, the weight ratio of rigid to flexible polyol ranges from
about 0.5 to about 20. In other embodiments, the ratio of rigid to
flexible polyol is about 1 to about 15. In other embodiments, the ratio
of rigid to flexible polyol is about 4 to about 15. In other embodiments,
the ratio of rigid to flexible polyol is about 3 to about 10. In other
embodiments, the ratio of rigid to flexible polyol is about 6 to about
12.

[0046] If more than one polyol is used to form the polyurethane
composition, mixtures of polyols can be used. In certain embodiments, the
polyurethane is formed by reaction of a first polyol and a second polyol.
In some of these embodiments, the first polyols has a functionality of at
least three and a hydroxyl number of about 250 to about 800, and more
preferably about 300 to about 400. In some embodiments, the first polyol
hydroxyl number is about 350 to about 410. In some of these embodiments,
the molecular weight of the first polyol ranges from about 200 to about
1000. In other embodiments, the molecular weight of the first polyol
ranges from about 300 to about 600. In other embodiments, the molecular
weight of the first polyol ranges from about 400 to about 500. Still, in
some embodiments, the molecular weight of the first polyol is about 440.

[0047] A second polyol can be used which produces a less rigid
polyurethane compared to a polyurethane produced if only the first polyol
is used. In some embodiments, the second polyol has a functionality of
about 3. In some embodiments, the functionality of the second polyol is
not greater than three. In these embodiments, the second polyol can have
a molecular weight of about 1000 to about 6000. In other embodiments, the
second polyol has a molecular weight of about 2500 to about 5000. In some
embodiments, the second polyol has a molecular weight of about 3500 to
about 5000. In some embodiments, the molecular weight is about 4800. In
other embodiments, the molecular weight of the second polyol is about
3000. In some of these embodiments, the second polyol has a hydroxyl
number of about 25 to about 70, and more preferably about 50 to about 60.

Fillers

[0048] As discussed above, one or more filler materials may be included in
the polyurethane composite material. In some embodiments, it is generally
desirable to use particulate materials with a broad particle size
distribution, because this provides better particulate packing, leading
to increased density and decreased resin level per unit weight of
composite. Since the inorganic particulate is typically some form of
waste or scrap material, this leads to decreased raw material cost as
well. In certain embodiments, particles having size distributions ranging
from about 0.0625 inches to below 325 mesh have been found to be
particularly suitable. In other embodiments, particles having size
distribution range from about 5 μm to about 200 μm, and in another
embodiment, from about 20 μm to about 50 μm.

[0049] Suitable inorganic particulates can include ground glass particles,
fly ash, bottom ash, sand, granite dust, slate dust, and the like, as
well as mixtures of these. Fly ash is desirable because it is uniform in
consistency, contains some carbon (which can provide some desirable
weathering properties to the product due to the inclusion of fine carbon
particles which are known to provide weathering protection to plastics,
and the effect of opaque ash particles which block UV light, and contains
some metallic species, such as metal oxides, which are believed to
provide additional catalysis of the polymerization reactions. Ground
glass (such as window or bottle glass) absorbs less resin, decreasing the
cost of the composite.

[0050] In general, fly ash having very low bulk density (e.g., less than
about 40 lb/ft3) and/or high carbon contents (e.g., around 20 wt %
or higher) are less suitable, since they are more difficult to
incorporate into the resin system, and may require additional inorganic
fillers that have much less carbon, such as foundry sand, to be added.
Fly ash produced by coal-fueled power plants, including Houston Lighting
and Power power plants, fly and bottom ash from Southern California
Edison plants (Navajo or Mohave), fly ash from Scottish Power/Jim Bridger
power plant in Wyoming, and fly ash from Central Hudson Power plant have
been found to be suitable for use in the invention.

[0051] Some embodiments of the polyurethane composite materials
additionally comprise blends of various fillers. In some of these
embodiments, the polyurethane composite materials exhibit better
mechanical such as impact strength, flexural modulus, and flexural
strength. One advantage in using blends of such systems is higher packing
ability of blends of fillers. For example, a 1:1 mixture of coal fly ash
and bottom ash has also been found to be suitable as the inorganic
particulate composition.

[0052] Example in Table 1: The examples below were all mixed in a
thermoset aromatic polyurethane system made with Hehr 1468 polyether
polyol (15% of the total weight of the non-ash portion), water (0.2%),
Air Products DC-197 (1.5%), Air Products 33LV amine catalyst (0.06%),
Witco Fomrez UL28 tin catalyst (0.02%), and Hehr 1426A isocyanate (15%).
1.5×3.5×24 inch boards were made.

[0053] Thus, embodiments of the polyurethane composite material which
comprise bottom and fly ash exhibit increased flexural strength and
flexural modules as compared to polyurethane composite material
comprising bottom ash alone. Some of these embodiments have a density of
about 65 lbs/ft3 to about 85 lbs/ft3, including about 65, 67,
69, 71, 73, 75, 77, 79, 81, 83, or 85 lbs/ft3.

[0054] In some of embodiments, the polyurethane composite material
comprising about 65% ash filler of which about 32.5 wt % was bottom ash
and about 32.5% was fly ash had a flexural strength of at least about
2300 psi, more preferably at least about 2400 psi, and even more
preferably at least about 2500 psi. In some of embodiments, the
polyurethane composite material comprising about 75% ash filler of which
about 37.5 wt % was bottom ash and about 37.5% was fly ash had a flexural
strength of at least about 2400 psi, more preferably at least about 2500
psi, and even more preferably at least about 2650 psi.

[0055] In some of embodiments, the polyurethane composite material
comprising about 65% ash filler of which about 32.5 wt % was bottom ash
and about 32.5% was fly ash had a flexural modulus of at least about 400
Ksi, more preferably at least about 440 Ksi, and even more preferably at
least about 460 Ksi. In some of embodiments, the polyurethane composite
material comprising about 75% ash filler of which about 37.5 wt % was
bottom ash and about 37.5% was fly ash had a flexural modulus of at least
about 640 Ksi, more preferably at least about 660 Ksi, and even more
preferably at least about 690 Ksi.

[0056] In some embodiments, slate dust can be added to the polyurethane
composite material to provide UV protection to the polyurethane composite
material. Some of these embodiments additionally comprise one or more of
pigments, light stabilizers, and combinations thereof. In some
embodiments, polyurethane composite materials comprising slate dust
exhibit substantially improved weathering. In some embodiments, the
polyurethane composite material comprises a dust. A dust may be selected
from at least one of slate dust, granite dust, marble dust, other
stone-based dusts, and combinations thereof. In some embodiments, the
polyurethane composite material comprises about 0.2 to about 70 wt %
dust. In other embodiments, the polyurethane composite materials comprise
about 10 to about 50 wt % of dust. In other embodiments, the polyurethane
composite materials comprise about 20 to about 60 wt % of dust. In other
embodiments, the polyurethane composite materials comprise about 30 to
about 55 wt % of dust. In some embodiments, dust may be added to the
composite material as additional filler. In this embodiment, the filler
that is not dust may be present in the composite in amounts from about 10
to about 70 weight percent and the dust may be added in amounts of about
5 to about 35 weight percent.

[0057] The following is an example of a polyurethane composite material
that comprises dust. The example should be in no way limiting, as other
embodiments will be readily understood by a person having ordinary skill
in the art.

[0058] Example from Table 2: In a blend of Cook Composites 5180 MDI (13.1%
by weight), 5205 polyol (3.91%), Dow DER (1.98%), antimony trioxide flame
retardant (3.52%), with Air Products DC-197 silicone surfactant (0.23%),
benzoyl peroxide (0.55%), and chipped slate (59.5%), with the added
pigments, carbon black and slate dust, all acting as UV inhibitors. The
light exposure was to a high fusion (UV light) chamber at AlliedSignal
Aerospace. Usually a 10 minute exposure in this chamber would deeply
discolor this resin system due to the yellowing of the MIDI-based
ingredients in the resin system.

[0059] In the above test, clearly slate dust provided better light
stability than coal ash, and the combination of slate dust plus carbon
black provided the best UV resistance, and had not failed yet in the 20
minute test (the only sample to not fail). The effect of the slate dust
was far more influential for UV stability then the various pigments
tested, including carbon black plus fly ash.

[0060] In some embodiments, the polyurethane composite material
composition comprises about 20 to about 95 weight percent of inorganic
filler, which includes, for example, approximately 20, 25, 30, 35, 40,
42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76,
78, 80, 82, 84, 86, 88, 90, 92, or 94 weight percent of filler. These
amounts may be based on the total of all of the fillers, such as one or
more of fly ash, dust, and fibrous material. However, the filler values
may also be representative of only one type of filler, e.g, fly ash. In
certain embodiments, the polymeric composite material may contain the
filler in an amount within a range formed by the two of the foregoing
approximate weight percent. In other embodiments, the polyurethane
composite material comprises about 40 to about 85 weight percent of the
filler. In other embodiments, the polyurethane composite material
comprises about 55 to about 80 weight percent of the filler. In other
embodiments, the polyurethane composite material comprises about 65 to
about 85 weight percent of the filler. In other embodiments, the
polyurethane composite material comprises about 40 to about 60 weight
percent of the filler. In other embodiments, the polyurethane composite
material comprises about 55 to about 70 weight percent of the filler.
Here, the unit "weight percent" refers to the relative weight of the
filler component compared to the total weight of the composite material.

Fibers

[0061] In some embodiments, reinforcing fibers can also be introduced into
the polyol mixture prior to introduction of the isocyanate. In some
embodiments, reinforcing fibers may be introduced after the at least one
polyol and the isocyanate are mixed. These can include fibers per se,
such as chopped fiberglass (chopped before or during mixing process such
as extrusion), or fabrics or portions of fabrics, such as rovings or
linear tows, or combinations of these. Typically, the reinforcing fibers
range from about 0.125 in. to about 1 in, more particularly from about
0.25 in to about 0.5 in. The reinforcing fibers give the material added
strength (flexural, tensile, and compressive), increase its stiffness,
and provide increased toughness (impact strength or resistance to brittle
fracture). Fabrics, rovings, or tows increase flexural stiffness and
creep resistance. The inclusion of the particular polyurethane networks
of the invention, together with the optional surfactants, and the
inorganic particulate sizes used make the composite of the invention
particularly and surprisingly well suited for inclusion of reinforcing
fibers in foamed material, which normally would be expected to rupture or
distort the foam bubbles and decrease the strength of the composite
system.

[0062] In addition to inclusion of reinforcing fibers into the polyol
mixture prior to polymerization, oriented axial fibers can also be
introduced into the composite after extrusion, as the polymer exits the
extruder and prior to any molding. The fibers (e.g., glass strings) can
desirably be wetted with a mixture of polyol (typically a higher
molecular weight, rigid polyol) and isocyanate, but without catalyst or
with a slow cure catalyst, or with other rigid or thermosetting resins,
such as epoxies. This allows the wetted fiber to be incorporated into the
composite before the newly added materials can cure, and allows this
curing to be driven by the exotherm of the already curing polymer in the
bulk material.

[0063] Whether added before or after polymerization and/or other mixing
processing such as extrusion, the dispersed reinforcing fibers may be
bonded to the polymeric matrix phase, thereby increasing the strength and
stiffness of the resulting material. This enables the material to be used
as a structural synthetic lumber, even at relatively low densities (e.g.,
about 20 to about 60 lb/ft3).

[0064] According to certain embodiments, many types of fibers may be
suitable for use in the polyurethane composite material. In some
embodiments, the polyurethane composite materials comprise at least one
of basalt, Wollastinite, other mineral fibers, or combinations thereof.
In some embodiments, these components may be used in place of or in
combination with glass fibers

[0066] In some embodiments, basalt fibers provide more flexural strength,
and flexural modulus to the highly-filled polyurethane composite
materials than fiberglass, and the combination of the two fibers gives a
synergistic effect on both measured properties.

[0067] In some of embodiments, the polyurethane composite material
comprising about 1.25% of chopped fiber glass and about 1.25% of basalt
had a flexural strength of at least about 2650 psi, more preferably at
least about 2700 psi, and even more preferably at least about 2730 psi.

[0068] Axial fibers or fabrics can also be added to the polyurethane
composite material. These fiber and/or fabric typically increase the
rigidity of the polyurethane composite material, and increase the
mechanical strength. Using thicker fibers, rovings, tows, fabrics or
rebar in the axial or stressed direction of the product can eliminate or
reduce the tendency of the plastic to creep with time or higher
temperature. These reinforcements also give higher initial tensile and
flexural strength, and higher flexural and tensile stiffness of the
polyurethane composite material. One advantage of using axial fibers or
fabrics is that the fibers or fabrics are oriented in a direction that
supports the polyurethane composite material. Unlike axial fibers,
randomly chopped fibers are less structurally supportive.

[0069] In some embodiments, the axial fibers or fabrics may be added while
dry (no resin on them). In other embodiments, the fibers or fabrics may
be "wet" with resin when mixed with the polyurethane composite material.
In some embodiments, the axial fibers or fabrics are added to the polyol
and catalyst premix. In other embodiments, the axial fibers or fabrics
are added to the isocyanate premix. Still, other embodiment may include
adding the axial fibers of fabric together with a slow or delayed
reaction polyol, catalyst, and isocyanate. Thus, the axial fibers can be
added with multiple components of the polyurethane composite material.

[0070] In some embodiments, the axial fibers or fabrics may be added to
the polyurethane composite material under tension, as is done with steel
rebar in structural concrete. This provides additional strength in the
tension direction, and in bending, as well as higher stiffness in the
tension and bending directions.

[0071] Example in Table 4: Glass and basalt fibers were implanted in a
highly-filled coal ash-thermosetting polyurethane mixture while still
uncured, and the fibers laid lengthwise down the urethane in a box mold,
and only on the top of the board (on one face). The fibers were laid in
the urethane mixture about 1/8 inch below the surface of the mix, but
frequently the fibers moved during the subsequent foaming and cure in the
closed box mold, and sometimes showed on the board surface.

[0072] The flexural properties were unaffected by this fiber movement. The
glass fibers from rovings were 0.755 g/ft, the basalt rovings from
Ahlstrom (Canada) were 0.193 g/ft. The boards were 1.5×3.5×24
inches. During flexural testing the boards were tested so that the
rovings were on the tensile side of the boards (not the compression
side). Some of the rovings were pre-wetted with the same resin system as
in the boards, but without the coal ash filler. The resin system was:
Bayer Multranol 4035 polyether polyol (16.6% by weight), Bayer Multranol
3900 polyether polyol (5.5%), Air products DC-197 silicone surfactant
(0.16%), water (0.07%), Witco Fomrez UL-28 tin catalyst (0.03%), Air
Products 33LV amine catalyst (0.10%), Coal fly ash (49%), Bayer MRS4 MDI
isocyanate (20.4%).

[0073] By wetting the glass fibers with uncured resin or cured resin, the
boards are considerably stronger--even stronger than basalt reinforced
boards with the same weight of fiber. By wetting the glass roving with
polyurethane resin, the strength of the glass roving exceeds that of the
unwetted basalt fiber.

[0074] In some embodiments, polyurethane composite materials comprising
less than about 1.5 wt % of glass fiber rovings prewet with resin had a
flexural strength of at least about 3500 psi and more preferably at least
about 4000 psi. In embodiments wherein the prewet glass fiber rovings
were procured with the polyurethane resin, the flexural strength was at
least about 150 Ksi, and more preferably at least about 180 Ksi.

Chain Extenders & Cross Linkers

[0075] In some embodiments of the polyurethane composite material, low
molecular weight reactants such as chain extenders or cross linkers
provide a more polar area in the polyurethane composite material. These
reactants allow the polyurethane system to more readily bind the
inorganic filler and/or inorganic or organic fibers in the polyurethane
composite material.

[0076] In some embodiments, the polyurethane composite material comprises
one or more selected from chain extenders, crosslinkers, and combinations
thereof. In some embodiments, the chain extenders can be selected one or
more from the group comprising ethylene glycol, glycerin, 1,4-butane
diol, trimethylolpropane, glycerol, or sorbitol. In some embodiments, at
least one cross linker may be used to replace at least a portion of the
at least one polyol in the polyurethane composite material. In some
cases, this results in reduced costs of the overall product.

[0077] In some embodiments which comprise chain extenders, the mechanical
properties of the polyurethane composite material are improved. In some
embodiments, chain extenders are not blocked from reacting with the
isocyanate by the filler. This is due to the molecular size of the chain
extenders. In some embodiments, the chain extenders result in better
mechanical properties as compared to polyurethane composite materials
with high filler inorganic loads, which do not use chain extenders. These
mechanical properties include flexural strength and modulus, impact
strength, surface hardness, and scratch resistance.

[0078] In other embodiments, polyurethane composite material comprising
chain extenders traps metals and metal oxides. This is advantageous in
highly filled polyurethane composite materials when the filler is coal or
other ashes, including fly ash and bottom ash, which can contain
hazardous heavy metals. In some embodiments, the polyurethane composite
material substantially prevents leaching of heavy metals in the
polyurethane composite material.

[0079] In some embodiments, a highly filled polymer composition comprising
chain extenders provides faster curing and less need for post-curing of
the polyurethane composite materials. In some embodiments, the chain
extenders provide better water resistance for the polyurethane composite
material. These chain extenders include diamine chain extenders, such as
MBOCA and DETDA. However, other embodiments of the polyurethane composite
material may comprise glycol extenders.

Blowing Agents

[0080] Foaming agent may also be added to the reaction mixture if a foamed
product is desired. While these may include organic blowing agents, such
as halogenated hydrocarbons, hexanes, and other materials that vaporize
when heated by the polyol-isocyanate reaction, it has been found that
water is much less expensive, and reacts with isocyanate to yield
CO2, which is inert, safe, and need not be scrubbed from the
process. In addition, CO2 provides the type of polyurethane cells
desirable in a foamed product (i.e., mostly closed, but some open cells),
is highly compatible with the use of most inorganic particulate fillers,
particularly at high filler levels, and is compatible with the use of
reinforcing fibers.

[0081] If water is not added to the composition, some foaming may still
occur due to the presence of small quantities of water (around 0.2 wt %,
based on the total weight of the reaction mixture) introduced with the
other components as an "impurity." Such water-based impurities may be
removed by drying of the components prior to blending. On the other hand,
excessive foaming resulting from the addition of too much water (either
directly or through the introduction of "wet" reactants or inorganic
particulate materials) can be controlled by addition of an absorbent,
such as UOP "T" powder.

[0082] The amount of water present in the system will have an important
effect on the density of the resulting composite material. This amount
generally ranges from about 0.10 wt % to about 0.40 wt %, based on the
weight of polyol added, for composite densities ranging from about 20
lb/ft3 to about 90 lb/ft3. However, polyurethane composite
material densities may be controlled by varying one or more other
components as well. In some embodiments, the overall density of the
polyurethane composite material may range from about 30 lb/ft3 to
about 80 lb/ft3. In some embodiments, the overall density of the
polyurethane composite material may range from about 40 lb/ft3 to
about 60 lb/ft3.

[0083] In some embodiments, the addition of excess blowing agent or water
above what is needed to complete the foam reaction adds strength and
stiffness to the polyurethane composite material, if the material is
restrained during the forming of the composite material. Typically,
excess blowing agent may be added to the polyol premixture. Such
excessive blowing agent may produce a vigorously foaming reaction
product. To contain such reaction product, a forming device that contains
the pressure or restrains the materials from expanding may be used. Such
forming devices are further described herein. The restraint of the
material or the higher pressure created by a mold or restraining forming
belts, causes higher pressure within the material which modifies the foam
cell structure, thus allowing higher mechanical properties of the
resulting cured material.

[0084] According to certain embodiments, use of excess blowing agent in
formation of the polyurethane composite material may also improves the
water resistance of the polyurethane composite material. In some
embodiments, use of excessive blowing agent may also increase the
thickness and durability of the outer skin of the self skinning
polyurethane composite material.

Solvents

[0085] The addition of solvents to the reaction mixture may also provide
certain advantages. In some embodiments of the polyurethane composite
materials, solvents can be added to the polyol premix prior to or during
the formation of the polyurethane. While it is described that solvents
are added to the polyol premix, solvents may also be added at other
stages of mixing of various components of the polyurethane composite
material. In some embodiments, the solvent may be added with any one or
more components of the reaction mixture which produces the polyurethane
composite material.

[0086] In some embodiments, addition of a solvent to a polyol premix
results in a polyurethane composite material that is more scratch and mar
resistance as compared to the same polyurethane composition made without
the solvent added to the polyol premix. Additional properties that result
in some embodiments include a harder skin. In addition, solvents may
cause a higher concentration of resin material to be in the self skinning
layer, as opposed to the fillers and reinforcing fibers. In some
materials, this provides a polyurethane composite material having a
higher concentration of ultraviolet stabilizers, antioxidants, and other
additives are closer to the outside of the composite material. In some
embodiments, use of solvent produces a polyurethane composite material
with an increases skin thickness. In other embodiments, the skin density
may also be increased. Still, in other embodiments, the addition of
solvents may decrease the interior density of the polyurethane composite
material.

[0087] In some embodiments, the addition of solvent to the polyol premix
substantially improves the weathering of the polyurethane composite
material due to the higher density and thickness of the outer skin, which
can contain more concentrated antioxidants, pigments, fillers and UV
inhibitors. In other embodiments, the addition of the solvent to the
polyol premix substantially prevents discoloration of the polyurethane
composite material when a sample of the material is exposed to sunlight
or UV radiation. In other embodiments, the addition of the solvent to the
polyol premix provides a polyurethane composite material (upon mixing of
the rest of the components) which has improved anti-static properties.

[0088] For example, the addition of about 2 to about 10 wt % of a solvent
selected from the group consisting of a hydrocarbon solvent (pentane,
hexane), carbon tetrachloride, trichloroethylene, methylene chloride,
chloroform, methyl chloroform, perchloroethylene, or ethyl acetate to a
polyol premix, the resulting self-skinning polyurethane composite
material has a thicker skin as compared to polyurethane composite
materials which are not create by the addition of a solvent to the polyol
premix. As a result, the outer skin is much thicker, including greater
than about 100, 200, 500, and about 1500% thicker as compared to a
polyurethane made without adding solvent to the polyol premix. In some
embodiments, the polyurethane composite material made by the addition of
solvent to the polyol premix may have an increase outer density skin,
thus making the skin harder, where the skin is greater than about 50, 75
and about 150% harder as compared to a polyurethane made without adding
the solvent to the polyol premix. Furthermore, some embodiments of the
polyurethane composite material have an interior density that is less
than between about 10 and about 50% as compared as compared to a
polyurethane made without adding the solvent to the polyol.

Additional Components

[0089] The polyurethane composite materials can contain one or more
compounds or polymers in addition to the foregoing components. Additional
components or additives may be added to provide additional properties or
characteristics to the composition or to modify existing properties (such
as mechanical strength or heat deflection temperature) of the
composition. For example, the polyurethane composite material may further
include a heat stabilizer, an anti-oxidant, an ultraviolet absorbing
agent, a light stabilizer, a flame retardant, a lubricant, a pigment
and/or dye. One having ordinary skill in the art will appreciate that
various additives may be added to the polymer compositions according to
embodiments of the invention. Some of these additional additives are
further described herein.

UV Light Stabilizers, Antioxidants, Pigments

[0090] Ultraviolet light stabilizers, such as UV absorbers, can be added
to the polyurethane composite material prior to or during its formation.
Hindered amine type stabilizers, and opaque pigments like carbon black
powder, can greatly increase the light stability of plastics and
coatings. In some embodiments, phenolic antioxidants are provided. These
antioxidants provide increased UV protection, as well as thermal
oxidation protection.

[0091] In some embodiments, the polyurethane composite material comprises
one or more selected from the group consisting of light stabilizers and
antioxidants. In combination, the light stabilizers and antioxidants
provide a synergistic effect of reducing the detrimental effects of UV
light as compared to either component used alone in the polyurethane
composite material. According to certain embodiments, the effect is
non-additive.

[0092] For example, in aromatic thermosetting polyurethanes, using 0.5 wt
% Tinuvin 328 light absorber alone provides some resistance to UV, such
as reduced yellowing, less chalking, and less embrittlement. Adding
Irganox 1010 antioxidant at 0.5 wt % greatly improves the resistance to
UV, and even using 0.2 wt % of each provides better stability than either
of the stabilizers at 0.5 wt % alone.

[0093] Pigment or dye can be added to the polyol mixture or can be added
at other points in the process. The pigment is optional, but can help
make the composite material more commercially acceptable, more
distinctive, and help to hide any scratches that might form in the
surface of the material. Typical examples of pigments include iron oxide,
typically added in amounts ranging from about 2 wt % to about 7 wt %,
based on the total weight of the reaction mixture.

Surfactants and Catalysts

[0094] One or more catalysts are generally added to control the curing
time of the polymer matrix (upon addition of the isocyanate), and these
may be selected from among those known to initiate reaction between
isocyanates and polyols, such as amine-containing catalysts, such as
DABCO and tetramethylbutanediamine, tin-, mercury- and bismuth-containing
catalysts. To increase uniformity and rapidity of cure, it may be
desirable to add multiple catalysts, including a catalyst that provides
overall curing via gelation, and another that provides rapid surface
curing to form a skin and eliminate tackiness. For example, a liquid
mixture of 1 part tin-containing catalyst to 10 parts amine-containing
catalyst can be added in an amount greater than 0 wt % and below about
0.10 wt % (based on the total reaction mixture) or less, depending on the
length of curing time desired. Too much catalyst can result in
overcuring, which could cause buildup of cured material on the processing
equipment, or too stiff a material which cannot be properly shaped, or
scorching; in severe cases, this can lead to unsaleable product or fire.
Curing times generally range from about 5 seconds to about 2 hours.

[0095] A surfactant may optionally be added to the polyol mixture to
function as a wetting agent and assist in mixing of the inorganic
particulate material. The surfactant also stabilizes and controls the
size of bubbles formed during foaming (if a foamed product is desired)
and passivates the surface of the inorganic particulates, so that the
polymeric matrix covers and bonds to a higher surface area. Surfactants
can be used in amounts below about 0.5 wt %, desirably about 0.3 wt %,
based on the total weight of the mixture. Excess amount of surfactant can
lead to excess water absorption, which can lead to freeze/thaw damage to
the composite material. Silicone surfactants have been found to be
suitable for use in the invention. Examples include DC-197 and DC-193
(silicone-based, Air Products), and other nonpolar and polar (anionic and
cationic) products.

Other Additives

[0096] In some embodiments, the filled polyurethane composite material
additionally comprises at least one coupling agent. Coupling agents and
other surface treatments such as viscosity reducers or flow control
agents can be added directly to the filler or fiber, and incorporated
prior to, during, and after the mixing and reaction of the polyurethane
composite material. In some embodiments, the polyurethane composite
materials comprise pre-treated fillers and fibers.

[0097] In some embodiments, the coupling agents allow higher filler
loadings of an inorganic filler such as fly ash. In embodiments, these
ingredients may be used in small quantities. For example, the
polyurethane composite material may comprises about 0.01 wt % to about
0.5 wt % of at least one coupling agent. In some of these embodiments,
the polyurethane composite materials exhibit greater impact strength, as
well as greater flexural modulus and strength, as compared to those
materials without at least one coupling agent. Coupling agents reduce the
viscosity of the resin/filler mixture. In some embodiments, coupling
agents increase the wetting of the fibers and fillers by the resin
components during the mixing the components.

[0098] In other embodiments, coupling agents reduce the need for colorants
by improving the dispersion of the colorants, and the break up of
colorant clumps. Thus, the polyurethane composite material which
comprises coupling agents and a colorant may exhibit substantially
uniform coloration throughout the polyurethane composite material.

[0099] Example in Table 5: The following flow control agents were tested
in a urethane polyol with a high loading of filler, such that the
combination would flow through a Zahn #5 cup viscometer. The polyol was
Bayer Multranol 4035 polyether used at 70 g, with 30 g of two different
fillers--tested separately. The polyol+filler were hand mixed and put
into the Zahn Cup with the bottom port closed with tape. When the Zahn
cup was full, the tape was removed and the time for the mixture to flow
out of the Cup was measured. All tests at 65° F. (18° C.).
The agents were: Air Products DABCO DC197 silicone-based surfactant,
Kenrich Petrochemicals Ken-React LICA 38, and Ken-React KR 55
organo-titanates, Shin-Etsu Chemical KBM-403 organo-silane.

[0100] These tests show that even 0.1% of the flow control agent on the
weight of the filler can markedly improve the flow of the mixture. This
flow improvement allows higher levels of filler to be used in urethane
mixtures, better wetting of the filler by the polyol, and more thorough
mixing of all the components. The DC-197 surfactant works well, but only
at much higher concentrations.

Ratios of the Components Used to Make the Polyurethane Composite Material

[0101] Variations in the ratio of the at least one polyol to the
isocyanate have various changes on the overall polyurethane product and
the process for making the polyurethane composites with high inorganic
filler loads. High filler in such systems typically inhibit or physically
block the reaction or action of the various polyurethane composite
components, including the at least one polyol, the di- or polyisocyanate,
the surfactants, flow modifiers, cell regulators and the catalysts. In
addition, the heat that is released during the course of the exothermic
reaction in forming the polyurethane composite is much higher in an
unfilled polyurethane system. A larger isocyanate index gives higher
temperature exotherms during the process of making the polyurethane
composite material. By adding, 5 to 20 wt % excess, and more preferably 5
to 10 wt % excess, of the isocyanate to the otherwise chemically balanced
at least one polyol that may comprise chain extenders with additional OH
groups (thus, measuring the balance by the overall OH numbers).

[0102] Higher temperature exotherms result in more cross linking of the
polyol and isocyanate, and/or a more complete reaction of the hydroxyl
groups and isocyanate groups. In some embodiments, a higher isocyanate
index also causes much higher cross link densities. In other embodiments,
the higher isocyanate index provides a more "thermoset" type of
polyurethane composite. In other embodiments, the higher isocyanate index
provides a polyurethane with a more chemically resistant polyurethane
composite material when exposed to chemicals. In some cases, these
chemicals are solvents and water. In certain embodiments, the higher
isocyanate index provides a polyurethane composite system with a higher
heat distortion temperature. The heat distortion temperature or its
effects may be determined by elevated temperature creep tests, standard
ASTM heat distortion testing, surface hardness variations with increased
temperature, for example, in an oven, and changes in mechanical
properties at increasing temperature.

[0103] Representative suitable compositional ranges for synthetic lumber,
in percent based on the total composite composition, are provided below:

[0104] At least one polyol: about 6 to about 28 wt %

[0105] Surfactant: about 0.2 to about 0.5 wt %

[0106] Skin forming catalyst about 0.002 to about 0.01 wt %

[0107] Gelation catalyst about 0.02 to about 0.1 wt %

[0108] Water 0 to about 0.5 wt %

[0109] Chopped fiberglass (optional) about 0.1 to about 10 wt %

[0110] Pigments (optional) 0.1 to about 6 wt %

[0111] Inorganic particulates about 60 to about 85 wt %

[0112] Isocyanate about 6 to about 20 wt %

[0113] Axial tows (optional) 0.1 to about 6 wt %.

[0114] Additional components described herein can be added in various
amounts. Such amount may be determined by persons having ordinary skill
in the art.

Mixing and Reaction of the Components of the Polyurethane Composite
Material

[0115] The polyurethane composite material can be prepared by mixing the
various components described above including the isocyanate, the polyol,
the catalyst, the inorganic filler, and various other additives. In some
embodiments, one or more other additives may be mixed together with the
components of the polyurethane composition. One or more component resins
can be heated to melt prior to the mixing or the composition may be
heated during the mixing. However, the mixing can occur when each
components is in a solid, liquid, or dissolved state, or mixtures
thereof. In one embodiment, the above components are mixed together all
at once. Alternatively, one or more components are added individually.
Formulating and mixing the components may be made by any method known to
those persons having ordinary skill in the art, or those methods that may
be later discovered. The mixing may occur in a pre-mixing state in a
device such as a ribbon blender, followed by further mixing in a Henschel
mixer, Banbury mixer, a single screw extruder, a twin screw extruder, a
multi screw extruder, or a cokneader.

[0116] In some preferred embodiments, the polyurethane composite material
can be prepared by mixing the polyols together (if multiple polyols are
used), and then mixing them with various additives, such as catalysts,
surfactants, and foaming agent, and then adding the inorganic particulate
phase, then any reinforcing fiber, and finally the isocyanate. While
mixing of some of the components can occur prior to extrusion, all of the
components may alternatively be mixed in a mixer such as an extruder.

[0117] In one embodiment, it has been found that this order of blending
results in the manufacture of polyurethane composite materials suitable
for building material applications. Thus, it has been discovered that the
order of mixing, as well as other reaction conditions may impact the
appearance and properties of the resulting polyurethane composite
material, and thus its commercial acceptability.

[0118] One particular embodiment relates to a method of producing a
polymer matrix composite, by (1) mixing a first polyol and a second
polyol with a catalyst, optional water, and optional surfactant; (2)
optionally introducing reinforcing fibrous materials into the mixture;
(3) introducing inorganic filler into the mixture; (4) introducing poly-
or di-isocyanate into the mixture; and (5) allowing the exothermic
reaction to proceed without forced cooling except to control runaway
exotherms.

[0119] The process for producing the composite material may be operated in
a batch, semibatch, or continuous manner. Mixing may be conducted using
conventional mixers, such as Banbury type mixers, stirred tanks, and the
like, or may be conducted in an extruder, such as a twin screw,
co-rotating extruder. When an extruder is used, additional heating is
generally not necessary, especially if liquid polyols are used. In
addition, forced cooling is not generally required, except for minimal
cooling to control excessive or runaway exotherms.

[0120] For example, a multi-zone extruder can be used, with polyols and
additives introduced into the first zone, inorganic particulates
introduced in the second zone, and chopped fibers, isocyanate, and
pigments introduced in the fifth zone. A twin screw, co-rotating,
extruder (e.g. 100 mm diameter, although the diameter can be varied
substantially) can be used, with only water cooling (to maintain
substantially near room temperature), and without extruder vacuum (except
for ash dust). Liquid materials can be pumped into the extruder, while
solids can be added by suitable hopper/screw feeder arrangements.
Internal pressure build up in such an exemplary arrangement is not
significant.

[0121] Although gelation occurs essentially immediately, complete curing
can take as long as 48 hours, and it is therefore desirable to wait at
least that long before assessing the mechanical properties of the
composite, in order to allow both the composition and the properties to
stabilize.

[0122] In some embodiments, the process of forming the highly filled
polyurethane composite material comprises providing the components of the
polyurethane composite material, mixing the components together,
extruding the components through a die, adding any other additional
components after the extrusion, and forming a shaped article of the
polyurethane composite material. As the polyurethane composite material
exits the die, the composite material may be placed in a mold for
post-extrusion curing and shaping. In one embodiment, the composite
material is allowed to cure in a box or bucket.

[0123] In one embodiment the formation of the shaped articles comprises
injecting the extruded polyurethane composite material in a mold cavity
and curing the shaped article. However, some embodiments require that the
extruded polyurethane composite material be placed in a mold cavity
secured on all sides, and exerting pressure on the polyurethane composite
material. In some of these embodiments, the polyurethane composite
material will be foaming or will already be foamed. However, it is
preferred that the material is placed under the pressure of the mold
cavity prior to or at least during at least some foaming of the
polyurethane composite material.

[0124] A shaped article can be made using the polyurethane composite
materials according to the foregoing embodiments. In some embodiments,
this article is molded into various shapes. In some embodiments, the
polyurethane composite material is extruded, and then injected into a
continuous production system. Suitable systems for forming the composite
materials of some embodiments are described in U.S. patent application
Ser. No. 10/764,013 filed Jan. 23, 2004 and entitled "CONTINUOUS FORMING
SYSTEM UTILIZING UP TO SIX ENDLESS BELTS," now published as U.S. Patent
Application Publication No. 2005-0161855-A1, and U.S. patent application
Ser. No. 11/165,071, filed Jun. 23, 2005, entitled "CONTINUOUS FORMING
APPARATUS FOR THREE-DIMENSIONAL FOAMED PRODUCTS," now published as U.S.
Patent Application Publication No. 2005-0287238-A1, both of which are
hereby incorporated by reference in their entireties.

[0125] The polyurethane composite material of certain embodiments may
exert certain pressures on the walls of any mold, such as that found in
the forming devices as described above. While the amount of pressure may
vary according to the amount of foaming and gas production, it is
preferred that such forming devices may exert or hold pressures by the
mold cavity ranging from about 35 to about 75 psi. In some embodiments,
the pressure is from about 45 to about 65 psi. In some embodiments, the
pressure is about 50 psi. However, mold pressures in any embodiment of a
method of making the polyurethane composite material can be higher than
or less than the specified values. The exact pressure required in the
formation of the desired shaped article depends on the density, color,
size, shape, physical properties, and the mechanical properties of the
article comprising the polyurethane composite material.

[0126] When foaming polyurethane is formed by belts into a product shape,
the pressure that the foamed part exerts on the belts is related to the
resulting mechanical properties. For example, as the pressure of the
foaming increases and the belt system can hold this pressure without the
belts separating, then the product may have higher flexural strength,
then if the belts allowed leaking, or pressure drop. In some embodiments,
pressures about 50 to about 75 psi have been used to obtain high
mechanical properties in the polyurethane composite material. In one
example, an increase in the flexural strength of 50 psi results from the
higher pressure in the belts, versus using a lower pressure.

[0128] Other shaped articles may comprise a portion of which comprises the
polyurethane composite material. In some embodiments, the polyurethane
composite material is coated or molded on one side of an article. For
example, the polyurethane composite material may be coated or molded onto
one side of a flat or S-shaped clay roof tile, which has been cut or
molded thinner than normal, and laid on a conveyor belt, followed by
extrusion of the polyurethane composite material onto at least a portion
of the tile. Such portion may be shaped by a mold which is adapted to
shape the polyurethane composite material deposited on the tile. For
example, the forming unit may operate with two mold belts which are
adapted to shape the polyurethane composite material on one side of the
portion. In some embodiments, the composite material may provide backing
to an article. In one embodiment, the composite material may be foamed
sufficient to provide insulation to an article.

[0129] In some embodiments, the polyurethane composite material can
reinforce an article. For example, by placing a coating or molding of the
polyurethane composite material on a roof tile, the impact strength of
the roof tile is increased. Thus one embodiment comprises a method of
substantially reducing the fracture of an article by depositing the
polyurethane composite on a solid surface article, shaping the composite
on the solid surface article by methods described herein, and curing the
composite on the solid surface article. Such method may produce a one or
more of a reinforced, backed, or insulated article. Such article may also
have increased physical and mechanical properties. Additionally, a
reinforcing layer may be used to prevent water weeping, and increases the
overall thickness of a solid surface article.

[0130] In some embodiments, the polyurethane composite material can bond
directly to an article solid surface article such as a tile.
Alternatively, an adhesive can be applied to the solid surface article
and a shaped polyurethane composite article can be attached thereto. A
solid surface article such as a tile may include at least one or more of
cement, slate, granite, marble, and combinations thereof; and the
polyurethane composite material as described in embodiments herein. Such
tiles may be used as roofing or siding tiles.

[0131] In some embodiments, the composite material may be used as
reinforcement of composite structural members including building
materials such as doors, windows, furniture and cabinets and for well and
concrete repair. In some embodiments, the composite material may be used
to fill any unintended gaps, particularly to increase the strength of
solid surface articles and/or structural components. Structural
components may formed from a variety of materials such as wood, plastic,
concrete and others, whereas the defect to be repaired or reinforced can
appear as cuts, gaps, deep holes, cracks.

Optional Additional Mixing Process

[0132] One of the most difficult problems in forming polyurethane
composite materials which have large amounts of filler is getting
intimate mixing--blending the polyols and the isocyanate. In some
embodiments, an ultrasound device may be used to cause better mixing of
the various components of the polyurethane composite material. In these
embodiments, the ultrasound mixing may also result in the enhanced mixing
and/or wetting of the components. In some embodiments, the enhanced
mixing and/or wetting allows a high concentration of filler, such as coal
ash to be mixed with the polyurethane matrix, including about 40, 50, 60,
70, 80, and about 85 wt % of the inorganic filler.

[0133] In some embodiments, the ultrasound device produces an ultrasound
of a certain frequency. In some embodiments, the frequency of the
ultrasound device is varied during the mixing and/or extrusion process.
In some embodiments, the components are mixed in a continuous mixer, such
as an extruder, equipped with an ultrasound device. In some embodiments,
an ultrasound device is attached to or is adjacent to the extruder and/or
mixer. In other embodiments, an ultrasound device is attached to the die
of the extruder. In other embodiments, the ultrasound device is placed in
a port of the extruder or mixer. In further embodiments, an ultrasound
device provides vibrations at the location where the isocyanate and
polyol meet as the screw delivers the polyol to the isocyanate.

[0134] In addition, an ultrasound device may provide better mixing for the
other components, such as blowing agents, surfactants, catalysts. In
embodiments where additional components are added to the polyol prior to
mixing the polyol with the isocyanate, the additional components are also
exposed to ultrasound vibration. In some embodiments, an ash selected
from fly ash, bottom ash, or combinations thereof, is mixed using an
ultrasound device. In some embodiments, ultrasound vibrations breaks up
filler and fiber bundles to allow more thorough wetting of these
components to provide a polyurethane composite material with better
mechanical properties, such as flexural modulus and flexural strength, as
compared to polyurethane composite materials which are created without
the use of ultrasound vibration. The wetting of fibers and fillers could
also be increased by the use of ultrasound at or near the die of the
extruder, thus forcing resin to coat the fibers and fillers better, and
even breaking up fiber bundles and filler lumps. The sound frequency and
intensity would be adjusted to give the best mixing, and what frequency
is best for the urethane raw materials, may not be best for the filler
and fibers. In another embodiment, one or more of the components may be
preblended in a mixer, such as a high shear mixer.

[0135] Unless otherwise noted, all percentages and parts are by weight.

[0136] The skilled artisan will recognize the interchangeability of
various features from different embodiments. Similarly, the various
features and steps discussed above, as well as other known equivalents
for each such feature or step, can be mixed and matched by one of
ordinary skill in this art to perform compositions or methods in
accordance with principles described herein. Although the invention has
been disclosed in the context of certain embodiments and examples, it
will be understood by those skilled in the art that the invention extends
beyond the specifically disclosed embodiments to other alternative
embodiments and/or uses and obvious modifications and equivalents
thereof. Accordingly, the invention is not intended to be limited by the
specific disclosures of embodiments herein. Rather, the scope of the
present invention is to be interpreted with reference to the claims that
follow.

Patent applications by Wade H. Brown, Mooresville, NC US

Patent applications by CENTURY-BOARD USA, LLC

Patent applications in class Including solid polymer formation in or during extruding step

Patent applications in all subclasses Including solid polymer formation in or during extruding step